1. Field of the Invention
The present invention relates to a recording method, and more particularly, to an improved recording method for providing a recorded matter having excellent fluorescence intensity of a recorded matter even after the ink was stored for a long time with high reliability in image formation. The present invention also relates to an ink cartridge suitable to be used to stably form a recorded matter having fluorescence, to a printing device capable of producing with high reliability a printed article having fluorescence, and to an information recording apparatus capable of stably recording information to fluoresce on a recorded medium.
2. Related Art
There have been various studies and reports on inks for pens or other writing utensils and inks for ink-jet recording. Particularly, with regard to improvement of print quality including fluorescence intensity and coloring properties of recorded matters, various proposals have been made for, for example, coloring materials of a novel structure suitable for respective use, an ink containing a coloring material having fluorescence properties (hereinafter referred to as xe2x80x9cfluorescent coloring materialxe2x80x9d) as a main coloring material, and an ink containing a fluorescent coloring material as one of the coloring materials of the ink. Particularly, the proposals of inks as a result of paying attention to the fluorescence properties of fluorescent coloring materials have been described in prior art including Japanese Patent Application Laid-Open Nos. 8-151545, 9-132729, 10-193775, 10-298462 and 10-298467 and Japanese Patent No. 2833038, and novel recording processes and/or fluorescent coloring materials have been proposed therein.
In addition to the above, the proposals of uses of fluorescent coloring materials have been presented in related art including Japanese Patent Application Laid-Open Nos. 5-293976, 6-191143, 6-322307, 7-009755, 7-305013, 8-053639, 9-003375, 9-001294, 9-137097, 9-137098, 9-137099, 9-165539, 9-241565, 9-255904, 9-286939, 10-007962, 10-183043, 11-080639, 11-320921 and 2000-038529, and Japanese Patent No. 2995853.
In recent years, the application of fluorescent coloring materials is not limited to the formation of beautiful color images. For example, a technical development has been proposed in which information (security information etc.) other than visual information is imparted by printing information such as characters, numerals, marks and/or bar codes on a recording medium with an ink having fluorescence properties, and by detecting the fluorescence emitted by the ink under irradiation of ultraviolet light of a desired wavelength. Accordingly, use of inks with fluorescence properties will expand to various application fields and development of inks being stable, reliable with excellent fluorescence intensity and coloring properties is much expected.
The coloring properties of ink on a recording medium, however, have been considered only in view of chromaticity (L*, a*, b*), i.e., a conventional measure for color. Even when a fluorescent coloring material is used, ink is designed in view of such a conventional measure, and the fluorescence developing ability of a fluorescent coloring material is far from being fully utilized at the present state. In other words, even in the above described proposals on utilization of fluorescent coloring materials, the fluorescent coloring materials are used only in view of the chromaticity (L*, a*, b*) not in view of fluorescence properties thereof, or they are used for their fluorescence but without taking notice of the fluorescence developing properties thereof, i.e., the fluorescence properties at an interface of the recorded matter. Thus, these proposals do not fully utilize the fluorescent properties of fluorescent coloring materials.
Accordingly, an object of the present invention is to provide an ink-jet recording method which can provide a recorded matter of which recorded part is imparted with fluorescence which is important for colors in nature by fully utilizing the fluorescence properties of a fluorescent coloring material; according to this method, high fluorescence intensity, high print quality including coloring ability, high reliability including long shelf life and ejection properties of ink are obtained, and as a result, stability and reliability of a recorded matter are improved.
Another object of the present invention is to provide an ink cartridge useable in stable formation of a recorded matter that can fluoresce.
A still further object of the present invention is to provide a printing device stably producing a recorded matter that can fluoresce.
A yet still further object of the present invention is to provide an information recording apparatus stably imparting fluorescent information to a recorded matter.
Such objects can be achieved by the present invention as described below.
According to one aspect of the present invention, there is provided a recording method which comprises a step of providing an ink from a recording head to a recording medium though a gap provided between the recording head and the recording medium, the ink being supplied to the recording head from an ink tank that comprises an ink contact member and the ink contacting the ink contact member, wherein the ink comprises
(i) a fluorescent coloring material;
(ii) a nonionic surfactant;
(iii) a compound which is not compatible to (ii); and
(iv) a liquid medium for dissolving or dispersing (i), (ii) and (iii),
and wherein the ink contact member comprises at least one compound selected from the group consisting of polyacetate and polyolefin.
According to another aspect of the present invention, there is provided an ink-cartridge which comprises an aqueous ink and an ink contact member, wherein the ink comprises:
(i) a fluorescent coloring material;
(ii) a nonionic surfactant;
(iii) a compound which is not compatible with (ii); and
(iv) a liquid medium for dissolving or dispersing (i), (ii) and (iii),
wherein the ink contact member comprises at least one compound selected from the group consisting of polyacetate and polyolefin.
According to still another aspect of the present invention, there is provided a printing apparatus comprising the above-described ink cartridge and an ink-jet head for discharging ink and placed in the ink cartridge.
According to still further aspect of the present invention, there is provided an information recording apparatus which comprises the above-described ink-cartridge and an ink-jet head for discharging ink placed in the ink-cartridge.